This invention relates to ladles, and more particularly, it relates to ladles suitable for use with molten metals such as molten aluminum.
In the prior art, ladles used for molten aluminum were fabricated from cast iron or from a refractory such as silica, mullite or alumina. Such ladles only lasted for about 2 or 3 days. Even if the cast iron ladle is coated with a refractory, it lasts only a few days because the refractory spalls off. Further, cast iron ladles have a high level of chilling power and, therefore, not only chill the melt as they are cyclically dipped, but have a great tendency to solidify the melt contained therein, particularly if the melt remains in the ladle for any extended time. In addition, molten metals such as molten aluminum wet cast iron leaving a film of metal, sometimes referred to as skull, that has to be removed from the ladle prior to its being re-immersed in the melt. Further, because of the high chilling power of cast iron, dissolved constituent in the melt tends to precipitate on the surface of the cast iron when the ladle is immersed in the molten aluminum. Such constituents tend not to re-dissolve, resulting in undesirable inclusions in the castings.
Thus, it will be seen that there is a great need for an improved ladle suitable for use with molten metals, e.g., aluminum which has an extended life, low chilling power and does not contribute to inclusions in cast products fabricated using such ladles.